Coin-Op Collection Presents: Midway Z/Y-Unit (MiSTerFPGA)

Tonight's release for the MiSTerFPGA platform covers Williams/Midway's Z-Unit and Y-Unit arcade hardware. Many changes come with this release, including the introduction of a new licensing portal for patrons to register their devices and generate keys.

Mortal Kombat (1992) releases to the Patron tier as the first ADPCM entry on the platform, while NARC (1988) and Smash T.V. (1990) release to the Patron Plus tier alongside Mortal Kombat, with NARC marking the first title using CVSD audio. Beta and Alpha tiers receive early access ahead of wider distribution.

Both platforms are built around the Texas Instruments TMS34010 graphics system processor, with the Y-Unit serving as the direct evolution of the Z-Unit design. Midway would later iterate on this architecture through the T-Unit and Wolf Unit platforms, establishing the foundation for arcade titles that defined the early 1990s.

This post covers a technical overview of both platforms along with updates on Midway's Z-Unit, Y-Unit, and T-Unit proposed release schedule for MiSTerFPGA and Analogue Pocket.

Licensing:

Alongside this release the new licensing portal is now live. Patrons sign in with their Patreon account to register devices, generate keys, and manage the licenses tied to their tier. While this release is MiSTerFPGA specific, the portal is built to serve both the MiSTerFPGA and Analogue Pocket platforms from the same dashboard.

Registration begins with the ChipID utility. A MiSTer build and a Pocket build are both downloadable from the portal, and each one is extracted to the root of the SD card before being launched on the target device.

ChipID displays a QR code containing the device's Hardware ID, and that code is captured from the portal's mobile companion (CoC-Licensing) using the Scan QR Code button, which is supported on both iOS and Android. Once the Hardware ID is captured, the device is named and submitted to the account.

From the dashboard, Generate Key produces a coinopkey.zip file. On MiSTer the archive is extracted to the root of the SD card, which places the key at games/mame/coinopkey.zip.

On Pocket it is extracted to the root of the SD card, which places the key at Assets/coinopkey/common/coinop.key. Each device has its own Hardware ID and must be registered and keyed separately.

Keys are generated on the 2nd of each month after Patreon processing completes, and a monthly key is valid for that month's cycle. Yearly subscribers receive a key that stays valid for the duration of the subscription and only needs to be regenerated at renewal.

Each account has a default allotment of one MiSTer and one Pocket registration. Additional registrations can be requested from an administrator on the Coin-Op Collection Discord or on Patreon.

A license can be moved to a different device by removing the old entry from the dashboard and registering a new one 30 days after the previous key was generated. A Hardware ID that was previously registered to another account can also be transferred to a new account through the same flow.

Full step-by-step instructions and an FAQ covering subscription lapses, multi-device setups, and transfers are available on the Help page of the portal.

At launch, Mortal Kombat is available to the Patron (Beta) tier and NARC and Smash T.V. are available to the Patron (Alpha) Plus tier in addition to Mortal Kombat. If a game is launched on a device whose account is not yet entitled to it, a QR code will appear on screen pointing to the Help page of the portal. This is expected behavior, and the QR code is the fastest path to verifying the device registration and key state for that account.

Overview:

The Z-Unit is built around a Texas Instruments TMS34010 graphics system processor running at 48 MHz. The video system outputs 512x400 at approximately 54.8 Hz, with pixel clocks derived at 16 MHz.

Sound is handled by a dedicated dual 6809 board operating at 8 MHz. The master 6809 drives a Yamaha YM2151 (OPM) FM synthesizer clocked at 3.579545 MHz, while the slave 6809 manages an HC55564 CVSD speech chip for digitized voice and effects. Two MC1408P8 8-bit DACs (U11, U12) handle analog mixing before the audio output stage.

The Y-Unit serves as the direct evolution of the Z-Unit design, retaining the TMS34010 main processor running at 40, 48, or 50 MHz speeds depending on the title. Resolution scales per title, with Smash T.V. running 400x256 and Mortal Kombat running 400x254.

Smash T.V. uses the CVSD sound board carried over from the Z-Unit lineage, with a 6809 driving the YM2151 at 3.579545 MHz alongside the HC55564 CVSD chip for digitized voice.

Mortal Kombat moves to a revised sound board built around an OKI M6295 ADPCM decoder running at 1 MHz in place of the HC55564, paired with the same 6809 and YM2151 arrangement. The MC1408P8 DAC pairing carries forward on both sound boards for final analog mixing.

Core Options:

On the MiSTerFPGA platform each title exposes a shared set of video and audio controls alongside its own game-specific menu.

NARC (Z-Unit)

Video options cover aspect ratio selection between original and full screen with two user-defined arcade ratios, vertical scaling between fill and integer modes, a force scandoubler toggle, and five scandoubler effects ranging from off through four CRT intensities.

Audio options enable or disable the OPM (YM2151), CVSD, and DAC channels independently, with a volume trim for each at 100%, 125%, 150%, or 175%.

Game settings include a Player 1 mapping swap, a synced mapping mirror for Player 2, and independent auto-fire targets for each player covering Fire, Rocket, or All, with rate selection exposed when auto-fire is active. A cheats master toggle gates a starting stage select for all eight NARC levels, per-player infinite lives, energy, invincibility, bullets, and rockets, and a set of triggerable cheats for adding dollars, drugs, and bust counts. A service menu entry is provided in the footer.

Smash T.V. (Y-Unit)

Video and audio controls match the layout used for NARC, with the same OPM, CVSD, and DAC channels and volume trims.

Game settings include the same player mapping and synced mapping pair, auto-fire with an All toggle and rate selection per player, and a cheats block covering invincibility, infinite lives, max speed, infinite ammo, and a weapon selector spanning Normal, 3-Way, Grenades, Balls, and Missiles. A service menu entry is provided in the footer.

Mortal Kombat (Y-Unit)

Video controls match the other titles. Audio replaces the CVSD channel with an MSM6295 PCM channel alongside the OPM and DAC, keeping the same per-channel enable and volume trim structure.

Game settings include player mapping and synced mapping, auto-fire with Off, HP, LP, HK, LK, or All per player, and rate selection per player. Under cheats are a stage select covering the seven tournament stages, per-player infinite energy, infinite time, infinite fatality time, EJB menu activation via BLK, CPU always fatality, secret game over, and double flawless. A Reptile block allows clues, speed, palette, and CPU Reptile to be toggled. A service menu entry is provided in the footer.

Updates:

Z-Unit and Y-Unit will release for the Analogue Pocket platform between April 26th and April 30th, arriving at the Patron tier. New additions for MiSTerFPGA will continue alongside the Pocket rollout across both the Patron and Patron Plus tiers as the platform expands.

T-Unit releases begin on May 1st and will continue the Williams/Midway rollout onto the next generation of the architecture.

Files will be available through the updaters once our organizational revamp is completed, and the standard should be run to pick up the new cores and updates on release day. Not all core releases will require a Patron membership, but the majority going forward will. I'll have more information about this in the coming week.

I’ll be traveling for business starting tomorrow, but I’ll still be available for support if needed. In my absence, the Coin-Op Collection Discord also has a group of members who helped test this system and can answer questions. Please don’t hesitate to ask for help if you need it.

Disclaimer: All product names, trademarks, and registered trademarks mentioned are the property of their respective owners. "Analogue", "Analogue Pocket", "MiSTer", "MiSTerFPGA", "OpenFPGA", "Williams", "Midway", "NARC", "Smash T.V.", "Mortal Kombat" and all derivative works are trademarks, registered trademarks, or copyrighted materials of their respective holders. Use of these names does not imply endorsement or association with this post. All rights reserved to their respective owners. This post is for educational and research purposes only.